Cylinder device



Sept 29, 1964 w. w. MGMULLEN 3,150,564

- CYLINDER DEVICE Filed Jan. s, 1962 2 sheets-sheet 1 Sept. 29, 1964 w. w. MoMuLLr-:N 3,150,554

CYLINDER DEVICE Filed Jan. a, 1962 2 sheets-sheet 2 fl /06l /06 /3 9691 /IVVE/VTOP 92 [WQ/IVE IV. MMULE/V United States Patent O aieasss CYLlNDER DEVHCE Wayne W. Melt/lullen, 1902 67th St., Des Moines, iowa Filed tian. 8, 1962., Ser. No. 164,944 3 Claims. (Cl. 91-2G7) My invention relates to hydraulic cylinders and the hydraulic circuit in which they function whereby versatility in the lifting or force transmission function of hydraulic power is achieved.

A specific object of my invention is to provide a hydraulic system incorporating a pair of cylinders interconnected in a pair of separate hydraulic circuits whereby one circuit can support a given load and the other circuit can be used primarily to move this load.

A further object of my invention is to provide a hydraulic system incorporating a pair of hydraulic cyiinders interconnected in a pair of separate hydraulic circuits whereby both circuits can cause displacement of the same movable parts of the cylinder.

A still further object of my invention is to provide a hydraulic system incorporating a pair of hydraulic cylinders interconnected in a pair of separate hydraulic circuits that can function at different pressure levels.

A still further object of my invention is to provide a hydraulic system incorporating a pair of hydraulic cylinders interconnected in a pair of separate hydraulic circuits whereby one circuit can function to displace the moving parts of said cylinders while the other circuit is still operatively connected to said cylinders.

A still further object of my invention is to provide a hydraulic cylinder that is adaptable for use in the above described hydraulic circuits and which has at least three compartments in communication with hydraulic fluid from one or the other of said hydraulic circuits.

A still further object of my invention is to provide a hydraulic system that is economical of manufacture and durable in use.

These and other objects will be apparent to those skilled in the art.

My invention consists in the construction, arrangements, and combination, of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in my claims, and illustrated in the accompanying drawing, in which:

FlG. l is a vertical sectional View of one of my hydraulic cylinders;

FG. 2 is a schematic' drawing of my hydraulic system showing both hydraulic circuits and both hydraulic cylinders with the movable portions of the respective cylinders being elevated to identical positions; and

FIG. 3 is a'view similar to that of FlG. 2 except that the movable portions of the respective cylinders are at different positions.

I have used the numeral lt) to generally designate an outer base cylinder comprised generally of a at bottom portion l2 and vertical side walls 14. Apertures lo in the protruding edges of bottom portion l2 can be used to facilitate the connection of cylinder l to a supporting surface 1S.

A vertical bore 2d is located in the center of bottom portion 1S and an upwardly extending shoulder 2l appears at the upper end thereof. Groove 22 is formed at the upper inner periphery of shoulder 2l. Bore 2d receives the lower end of vertical shaft 24 which is shaped to rest on groove 22 before terminating in the lower portion of bore 20. Shaft 24 is rigidly secured to cylinder l@ by weldments 26 and Z7. A shoulder 28 extends outwardly from shaft 24 at a point just below its upper end. The center bore 29 of a stationary piston 30 receives the extreme upper end of shaft 214 whereby the piston rests on the shoulder 2S of the shaft. A threaded bore 32 appears in the center of the upper end of shaft 24. Shaft 3d has a diameter equal to that of shaft 24. A shoulder 3d similar to shoulder 23 on shaft 24 extends outwardly from shaft 3d at a point just above the threaded lower end of shaft 34. The threaded lower end of shaft 34 is received in the center bore 29 of piston Sii and is threadably received within the threaded bore 32 in the upper end of shaft 2d. Thus, the piston 39 is held in a stationary position between the similar shoulders 2S and 36 of two similar shafts 24 and 34, respectively. Shaft 34 extends upwardly from piston 3i) and can have stop element 33 detachably secured to its upper end in any convenient manner.

A movable inner cylinder 4t) having an outside diameter substantially equal to the inside diameter of base cylinder l@ is siidably mounted within and projectingy from the upper end of cylinder l0. Cylinder eti is comprised generally of bottom portion 42, vertical side walls and top portion de. A flange S3 is secured to and protrudes outwardly from top portion d6 and apertures di? therein to facilitate the attachment of the flange to an object or component part of related equipment which is to be forcibly moved. A Vertical bore 52 in bottom portion i2 of cylinder dit slidably receives shaft 24. Similarly, vertical bore 54 in the center of top portion i6 of cylinder d@ slidably receives shaft 34.. Sealing elements S6 and 58 effect a seal between cylinder and shaft 3d; elements 6@ and 62 effect a seal between piston 3@ and cylinder dii; sealing ring 6d mounted on the upper periphery of cylinder iii assists in effecting a seal between cylinders lli) and dii, as does sealing ring 66 on the lower end of cylinder dii; and eiernents 68 and 7@ effect a seal between the lower end of cylinder Lil) and shaft 24.

As shown in FIG. l, a hydraulic fluid compartment 72 is formed between the bottom portions of the two cylinders ld and di?. A second hydraulic fluid compartment 74 is located between stationary cylinder 30 and the bottom portion d2. of inner cylinder ed. A third hydraulic duid compartment 76 is located between stationary piston 3@ and the upper portion 46 of inner cylinder di?.

A port '73 in the upper portion 46 of cylinder di) communicates with passageway 3@ which in turn communi- Cates with fluid compartment '76. A port S2 in the bottom portion l2 of cylinder it) terminates in passageway 84 which in turn registers with passageway 8e in shaft 24. rhe upper end of passageway S6 communi- Cates with duid compartment 7d. Port 88 in the lower portion of cylinder l? communicates directly with iiuid compartment 72.

ln FGS. 2 and 3, I have shown pairs of the hydraulic cylinder just described, and the second cylinder in each of these figures will have the letter A following the numeral identification of its component parts so that, for example, shaft in one cylinder will correspond to shaft 34A in the other cylinder.

A conduit 96 connects the fluid compartments 76 and 76A in the pairs of cylinders shown in both FIGS. 2 and 3. Conduit 9@ effects this connection by extending between ports Si) and 33A in the respective base cylinders it) and ltiA. A conventional hydraulic power source comprised of pump 92, reservoir 94 and vaive 96 is interposed within conduit 9d. Valve 96 is actuated by lever 9d whereby the flow of hydraulic fluid to or from the reservoir 94 can be stopped, or the flow of fluid can be directed either towards or away from the reservoir.

A conduit liti? extends between port '7S on upper cylinder dal and port `82A on base cylinder lliA to connect fluid compartments '72 and 74A. Similarly, a conduit Titi?. extends between port 73A on upper cylinder 40A and port 82 on base cylinder 1@ to connect fluid compartments 72A and 74. A second conventional hydraulic power source comprised of pump d, reservoir 1616 and valve 103 is interposed between conduits 100 and 162 by conduits 11i) and 112. Conventional valve 108, as actuated by lever 113, can divert the flow of pressure fluid away from the reservoir 166 towards either conduit 11) or 112. Valve 108 can also be actuated to prevent the flow of fluid through the pump 104 and reservoir, and can also be moved to a fourth position whereby a free flow of fluid can pass through the reservoir and pump in either direction.

The normal operation of my device is as follows: The base cylinders 16 and 10A can be mounted on or secured to any desirable supporting surface 18. This supporting surface could be a floor surface or a frame member of any equipment having need for equipment of this character. The load or component part to be moved or lifted is mounted on or secured to the flanges 48 and 48A on the upper ends of inner cylinders 40 and 40A, respectively. Normally, the bottom portions 42 and 42A of inner cylinders 40 and ti-A, respectively, are resting on the top of shoulders 21 and 21A in the base cylinders 1t) and 19A wherein the compartments '76 and 72 are considerably reduced in volume, and the compartment '74 is greatly enlarged in volume. It can be assumed that all fluid compartments in all cylinders, as Well as related conduits, are filled with any desirable hydraulic fluid.

The valve 103 can be moved to a position whereby fluid can freely flow through the pump 164 and reservoir 1% in any direction that it chooses to take. The valve 96 is moved to a position whereby fluid under pressure will flow from pump 92 and reservoir 94 when the pump is actuated. The starting of pump 92 Will thereupon force fluid into conduit 90, and thence into the compartments '76 and 76A of base cylinders 10 and lflA, respectively. The introduction of fluid into these compartments exerts an upward force on the bottoms of cylinders 40 and 40A, and these cylinders will uniformly rise as depicted in FiG. 2.

In certain environments, it is sometimes desirable to raise a load, and then to change its then level position to an angularly disposed position. This would be the case, for example, in an industrial assembly table. In such a situation, the table could be raised in the manner described. To then change the elevation of the loadsupporting flanges 48 on the top of cylinders 4t) and 40A, the valve 96 could then be moved to a position whereby no fluid could be exhausted out of conduit 9d into reser- Voir 94. If it is desired to raise inner cylinder 40A and to lower cylinder 40, valve 10S is actuated to permit pump 104 to force hydraulic fluid into the circuit through conduit 112. Fluid is thereby forced under pressure through conduits 112 and 152 into compartments 72A and 74 to cause the desired result. Since piston 39A will not move, the introduction of fluid into compartment 72A will force cylinder 40A upwardly. Similarly, since piston 39 cannot move, the introduction of fluid into chamber 74 will cause cylinder i6 to move downwardly. Fluid is thereupon flushed out of compartment 74A through conduit 16) towards compartment 72. This flow of fluid would ordinarily impede the desired result except that the fluid flowing through conduit 106 towards compartment 72 will be exhausted through conduit 110 back towards reservoir 166.

As the volumes of compartments '72, 72A, 74 and 74A are changing from the above-described action, the volume of compartments 76 and '76A also are changing. The fluid in the decreasing compartment 76 is merely flushed through conduit 90 into the then enlarging compartment 76A. The cylinders it? and 49A can be held in the above described position by moving valve 1% to a position whereby no fluid could move away from or towards reservoir 106. Alternate positions of inner cylinders 4f) and 49A can be obtained by reversing valve 108 so that conduit 11i) then becomes the pressure line and conduit 112 serves as the return line. The flanges 48 and 48A on the upper ends of the movable inner cylinders 40 and 40A, respectively, can be subsequently leveled and lowered by actuating valve 108 whereby free flow of liquid can take place in the circuit, and valve 96 is actuated to permit the return of fluid from compartments 76 and 76A, and conduit 90, back to reservoir 94.

From the foregoing, it is seen that the lower7 hydraulic circuit consisting of compartments 76 and 76A, conduit 99, valve 96, reservoir 94 and pump 92, has the great burden of lifting and supporting the load. The auxiliary hydraulic circuit comprised of compartments 72, 72A, 74 and 74A, conduits 100, 102, 110 and 112, valve 168, reservoir 106 and pump 104 is then able to move the load as it is being supported by this lower hydrauiic circuit. As a consequence, the auxiliary hydraulic circuit requires much less horsepower to operate, and smaller sealing components can be used in this circuit since smaller pressures are encountered. This greatly enhances the economy of constructing and operating the entire system, and these are among other advantages that flow from the application of these two hydraulic circuits to the type of cylinders described.

Thus, it is seen that my device will accomplish at least all of its stated objectives.

Some changes may be made in the construction and arrangement of my cylinder device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim:

1. In combination,

first and second cylinder units, each cylinder unit comprising,

a base cylinder having an open top and a closed bottom portion,

a shaft means rigidly secured to the bottom portion of said base cylinder and extending upwardly and outwardly from the upper end thereof,

a movable cylinder slidably mounted on said shaft means and having at least one of its ends slidably mounted within said base cylinder,

a piston element rigidly secured to said shaft Within said movable cylinder to form separate fluid compartments within said movable cylinder above and below said piston element,

and fluid conducting means for introducing hydraulic fluid into each of said compartments and into the bottom of said base cylinder,

a first hydraulic circuit including a first conduit connecting the bottom interior portions of said two base cylinders,

and a first hydraulic power means in communication with said first conduit whereby hydraulic fluid can be introduced into or removed from the bottom interior portions of said two base cylinders,

a second hydraulic circuit including separate conduits connecting the compartment above said piston in each cylinder unit with the compartment below said piston in the other cylinder unit,

a third conduit connecting the said separate conduits,

and a second hydraulic power means interposed within said third conduit whereby hydraulic fluid can be selectively forced through said second and third conduits at different times either towards or away from said compartments.

2. The structure of claim l wherein said rst hydraulic power means includes a valve which can selectively prevent the return of fluid to said hydraulic power means from said first conduit.

3. The structure of claim 1 wherein said first hydraulic power means includes a Valve which can selectively prevent the return of fluid to said hydraulic power means from said rst conduit; and said second hydraulic power means includes a valve which at diierent times can selectively prevent the ow of fluid in Said second hydraulic circuit, can permit free ow of fluid through said second hydraulic circuit, or which can divert the flow of fluid either towards or away from each of said separate conduits.

References Cited in the file of this patent UNITED STATES PATENTS Smith Sept. 8, Dinzl Mar. 15, Hoar et al. May 2, Fagge Sept. 16, Flowers Feb. 10,

Russell May 10, 

1. IN COMBINATION, FIRST AND SECOND CYLINDER UNITS, EACH CYLINDER UNIT COMPRISING, A BASE CYLINDER HAVING AN OPEN TOP AND A CLOSED BOTTOM PORTION, A SHAFT MEANS RIGIDLY SECURED TO THE BOTTOM PORTION OF SAID BASE CYLINDER AND EXTENDING UPWARDLY AND OUTWARDLY FROM THE UPPER END THEREOF, A MOVABLE CYLINDER SLIDABLY MOUNTED ON SAID SHAFT MEANS AND HAVING AT LEAST ONE OF ITS ENDS SLIDABLY MOUNTED WITHIN SAID BASE CYLINDER, A PISTON ELEMENT RIGIDLY SECURED TO SAID SHAFT WITHIN SAID MOVABLE CYLINDER TO FORM SEPARATE FLUID COMPARTMENTS WITHIN SAID MOVABLE CYLINDER ABOVE AND BELOW SAID PISTON ELEMENT, AND FLUID CONDUCTING MEANS FOR INTRODUCING HYDRAULIC FLUID INTO EACH OF SAID COMPARTMENTS AND INTO THE BOTTOM OF SAID BASE CYLINDER, A FIRST HYDRAULIC CIRCUIT INCLUDING A FIRST CONDUIT CONNECTING THE BOTTOM INTERIOR PORTIONS OF SAID TWO BASE CYLINDERS, AND A FIRST HYDRAULIC POWER MEANS IN COMMUNICATION WITH SAID FIRST CONDUIT WHEREBY HYDRAULIC FLUID CANBE INTRODUCED INTO OR REMOVED FROM THE BOTTOM INTERIOR PORTIONS OF SAID TWO BASE CYLINDERS, A SECOND HYDRAULIC CIRCUIT INCLUDING SEPARATE CONDUIT CONNECTING THE COMPARTMENT ABOVE SAID PISTON IN EACH CYLINDER UNIT WITH THE COMPARTMENT BELOW SAID PISTON IN THE OTHER CYLINDER UNIT, A THIRD CONDUIT CONNECTING THE SAID SEPARATE CONDUITS, AND A SECOND HYDRAULIC POWER MEANS INTERPOSED WITHIN SAID THIRD CONDUIT WHEREBY HYDRAULIC FLUID CAN BE SELECTIVELY FORCED THROUGH SAID SECOND AND THIRD CONDUITS AT DIFFERENT TIMES EITHER TOWARDS OR AWAY FROM SAID COMPARTMENTS. 